ok guys I have a real problem here, I am working on my uncle's 98 xlt 4.2 5-spd that randomly died the other day. the truck has a fairly new fuel sender unit. I am not getting any pulse signals when cranking to the 3 signal wires on the coil pack but I do have 12v key on hot to it, also the fuel pump relay is not grounding when key is turned to on or start!!! when I jump the ground of the coil side of fuel pump really to chassis ground the pump turns on like it should. I was also not getting a 12v key on signal to the fuel pump relay earlier which I fixed by swapping out the ecm. so so far I replaced the cps sensor and tried 2 boneyard ecms and still nothing!!! has anyone else had a similar problem?? I am in need of some series help here I cant figure this damn thing out!!! thanks guys

 

First thing is to put the original PCM back in.
If you do not see any PCM coil driver action at cranking, the PCM has no power to it.
.
At key on, no crank the PCM closes ground to the pump circuit for about 1 second then opens up..
Absent this and no pulses to the coils the PCM is not being powered up.
Fuse, relay or wiring.
Good luck.